Methods and apparatus for noise attenuation in an engine nacelle

Patent metadata

Field	Value
Publication number	US-9604438-B2
Application number	US-201414266071-A
Country	US
Kind code	B2
Filing date	Apr 30, 2014
Priority date	Apr 30, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

An acoustic liner includes a first core that has a plurality of first core cells defined by a corresponding plurality of first core cell walls. The first core has a first core thickness. The acoustic liner also includes a second core that has a plurality of second core cells defined by a corresponding plurality of second core cell walls. The second core has a second core thickness, and the first core thickness and the second core thickness are unequal. The acoustic liner further includes a second fabric sheet coupled between the first core and the second core. Each of the plurality of second core cell walls generally is not coplanar with any of the plurality of first core cell walls.

First claim

What is claimed is:

1. An acoustic liner comprising:
a first core comprising a plurality of first core cells defined by a corresponding plurality of first core cell walls, said first core having a first core thickness;
a second core comprising a plurality of second core cells defined by a corresponding plurality of second core cell walls, said second core having a second core thickness, wherein said first core thickness and said second core thickness are unequal; and
a second fabric sheet coupled between said first core and said second core, wherein said second fabric sheet is secured to said first core by a first reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of said first core cells and second fabric sheet, wherein said second fabric sheet is secured to said second core by a second reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of said second core cells and second fabric sheet, and wherein each of said plurality of second core cell walls generally is not coplanar with any of said plurality of first core cell walls.

2. The acoustic liner according to claim 1 , further comprising an acoustic liner facesheet coupled to said first core, said acoustic liner facesheet includes a plurality of orifices each extending therethrough.

3. The acoustic liner according to claim 2 , further comprising a first fabric sheet coupled between said acoustic liner facesheet and said first core.

4. A nacelle for an engine, said nacelle comprising:
an acoustic liner comprising:
a first core comprising a plurality of first core cells defined by a corresponding plurality of first core cell walls, said first core having a first core thickness;
a second core comprising a plurality of second core cells defined by a corresponding plurality of second core cell walls, said second core having a second core thickness; and
a second fabric sheet coupled between said first core and said second core, wherein said second fabric sheet is secured to said first core by a first reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of said first core cells and second fabric sheet, wherein said second fabric sheet is secured to said second core by a second reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of said second core cells and second fabric sheet; and
a structural inner barrel coupled to said nacelle, said structural inner barrel comprising a third core comprising a plurality of third core cells defined by a corresponding plurality of third core cell walls, wherein said acoustic liner is coupled to said structural inner barrel.

5. The nacelle according to claim 4 , wherein said acoustic liner further comprises an acoustic liner facesheet coupled to said first core, said acoustic liner facesheet includes a plurality of orifices each extending therethrough.

6. The nacelle according to claim 5 , wherein said acoustic liner further comprises a first fabric sheet coupled between said acoustic liner facesheet and said first core.

7. The nacelle according to claim 5 , wherein each of said plurality of orifices is elongated in a direction of airflow through said nacelle past said acoustic liner.

8. The nacelle according to claim 7 , wherein said plurality of orifices is arranged on said acoustic liner facesheet such that said acoustic liner facesheet has a porosity in a range of about 15 to about 30 percent open area.

9. The nacelle according to claim 4 , wherein each of said plurality of third core cell walls generally is not coplanar with any of said plurality of first core cell walls and generally is not coplanar with any of said plurality of second core cell walls.

10. The nacelle according to claim 4 , wherein each of said third core cells has a characteristic cross-sectional diameter that is not equal to a characteristic cross-sectional diameter of each of said first core cells and is not equal to a characteristic cross-sectional diameter of each of said second core cells.

11. The nacelle according to claim 4 , wherein said first core thickness and said second core thickness are unequal.

12. The nacelle according to claim 4 , wherein each of said plurality of second core cell walls generally is not coplanar with any of said plurality of first core cell walls.

13. A method of making a nacelle, said method comprising:
disposing a second fabric sheet generally concentrically about a first core, wherein the first core comprises a plurality of first core cells defined by a corresponding plurality of first core cell walls, the first core having a first core thickness;
disposing a second core generally concentrically about the second fabric sheet, wherein the second core comprises a plurality of second core cells defined by a corresponding plurality of second core cell walls, the second core having a second core thickness
coupling the second fabric sheet between the first core and the second core, such that the second fabric sheet is secured to the first core by a first reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of the first core cells and the second fabric sheet, and such that the second fabric sheet is secured to the second core by a second reticulated film adhesive to facilitate avoiding interference with an acoustic coupling of the second core cells and the second fabric sheet; and
coupling the second core to a structural inner barrel.

14. The method according to claim 13 , further comprising coupling an acoustic liner facesheet to the first core, wherein the acoustic liner facesheet includes a plurality of orifices each extending through the acoustic liner facesheet.

15. The method according to claim 14 , wherein said coupling the second fabric sheet between the first core and the second core comprises coupling the second fabric sheet between the first core and the second core such that each of the plurality of second core cell walls generally is not coplanar with any of the plurality of first core cell walls.

16. The method according to claim 15 , wherein said coupling the acoustic liner facesheet comprises coupling the acoustic liner facesheet wherein the plurality of orifices is arranged such that the acoustic liner facesheet has a porosity in a range of about 15 to about 30 percent open area.

17. The method according to claim 14 , further comprising coupling a first fabric sheet between the acoustic liner facesheet and the first core.

18. The method according to claim 13 , wherein said coupling the second core to the structural inner barrel comprises coupling the second core to a third core, wherein the third core comprises a plurality of third core cells defined by a corresponding plurality of third core cell walls.

19. The method according to claim 18 , wherein said coupling the second core to the third core comprises coupling the second core to the third core such that each of the plurality of third core cell walls generally is not coplanar with any of the plurality of first core cell walls and generally is not coplanar with any of the plurality of second core cell walls.

20. The method according to claim 18 , wherein said coupling the second core to the third core comprises coupling the second core to the third core wherein each of the third core cells has a characteristic cross-sectional diameter that is not equal to a characteristic cross-sectional diameter of each of the first core cells and is not equal to a characteristic cross-sectional diameter of

Assignees

• Boeing Co

Inventors

• Lumbab Alex C
• Leisten Bradley Scott

Classifications

• B32B2597/00

  Tubular articles, e.g. hoses, pipes · CPC title

• Y10T156/10

  Methods of surface bonding and/or assembly therefor · CPC title

• B32B37/12 Primary

  characterised by using adhesives · CPC title

• F05D2250/283

  honeycomb · CPC title

• F05D2260/96

  Preventing, counteracting or reducing vibration or noise · CPC title